Method for constant tension and slippage setting on a reel using accelerometers to detect rotational direction

ABSTRACT

The present invention is a reel apparatus, system and method of using same that may utilize accelerometers for determining the rotational direction of an offshore reel as a component of maintaining a constant tension and constant slippage setting on the umbilical of the offshore reel as the radius to the umbilical varies and the deployment direction is reversed.

CROSS-REFERENCE TO RELATED APPLICATIONS

Priority is claimed from provisional application U.S. ProvisionalApplication Ser. No. 62/174,368 filed on Jun. 11, 2015, and incorporatedby reference herein.

BACKGROUND OF INVENTION

1. Field of the Invention

In general, the present invention relates to an apparatus, system andmethod for a self-adjusting intelligent reel assembly. Moreparticularly, the present invention provides a new and improved reelassembly that may use accelerometers for determining the rotationaldirection of an offshore reel as a component of maintaining a constanttension and constant slippage setting on the umbilical of the offshorereel as the radius to the umbilical varies and the deployment directionis reversed.

2. Description of the Prior Art

When subsea blowout preventer stacks are lowered to the seafloor tofacilitate the drilling of oil and gas wells, they are lowered on adrilling riser, which has a long conduit with an inner diametertypically about nineteen inches, which acts as the main conduit for thedrilling operations. On the outside of this conduit will be flotationmaterial to make it lighter in water, high pressure circulation linescalled choke and kill lines, and control umbilicals. The controlumbilicals can be hydraulic, electrical, fiber optic, or a combinationof these.

The umbilicals are clamped to the high pressure lines on the riser suchthat the drilling riser carries the weight of the deployed lines. Theumbilicals are handled at the surface by reels which must payout theumbilical when the drilling riser is lowered and rewind the umbilicalwhen the drilling riser is retrieved. Umbilicals may be hoses, wirerope, cable, hoses, fiber optics, electrical, or combinations of these.

A first level of control of these reels was to have a valve controllinga motor on the reels and simply keep up with the movement of thedrilling riser. This was made practical with a “service loop” which sentthe umbilicals over a first sheave, down a loose loop, back up over asecond sheave, and then clamped to the riser.

A next level of control was to simply use an air throttle and put theumbilical in tension at all times. When the drilling riser is lowered,it pulls the motor against the pneumatic supply and pumps air back intothe air system, somewhat like regeneration, or dumped the generated airacross a relief valve. Dumping the generated air is more workable as thepneumatic supply is likely of too high a pressure to pump back into. Asthe radius to the umbilical being deployed from a full spool to an emptyspool can vary by as much as 3/1, an umbilical tension of 1,000 lbs. atthe outer wrap will translate into 3,000 lbs. at the inner wrap. Thismeans that you must have personnel monitoring the reel to keep thetension down with a reasonable range. Furthermore, you have a slipclutch to prevent high tension if a drilling riser is lowered when thebrakes are set on the reel; a slip clutch setting of 1,500 lbs. at theouter wrap becomes a slip clutch setting of 4,500 lbs. at the innerwrap.

What this means is that in all these cases, personnel must be committedto monitor and control the umbilical tension at all times during therunning operations. This added head count in a space constrainedexpensive offshore rig is required at the critical time when the blowoutpreventer stack and drilling riser is run and personnel commitment is atthe maximum.

Even with the added personnel commitment to monitor and control theumbilical tension, no solution has been available for this high safetyslippage setting when the umbilical is being paid off from the innerwraps. With the long studies of trying to reduce personnel requirementson these offshore rigs, there has been no solution offered for theseproblems.

Prior art attempts at improvements to this problem have obviously notprovided the desired solutions. Thus, there is a need for an apparatus,process and or system that provides a self-adjusting intelligent reelassembly for reels. The above discussed limitations in the prior art isnot exhaustive. The current invention provides an inexpensive, timesaving, more reliable apparatus, method and system for reels where theprior art fails.

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages inherent in the known types ofreels utilized with offshore applications now present in the prior art,the present invention provides a new and improved reel apparatus, systemand method of using same. As such, the general purpose of the presentinvention, which will be described subsequently in greater detail, is toprovide a new and improved reel which has all the advantages of theprior art devices and none and or fewer of the disadvantages.

It is, therefore, contemplated that the present invention is anapparatus, system and method of using dual accelerometers inautomatically determining a direction of rotation of a spool on a reelas a component of automatically maintaining a relatively constanttension and a relatively constant slippage load on an umbilical which isdeployed from said spool on said reel by being clamped to a subseadrilling riser where said relatively constant tension is determined by amotor torque on a motor and said relatively constant slippage load isdetermined by a frictional load on one or more slip clutches,comprising: determining an initial radius to said umbilical on saidspool, a diameter of said umbilical, a distance between a first sideflange and a second side flange of said spool, and a distance of saidumbilical from said first side flange of said spool; counting therotations of said spool; and determining said direction of rotation ofsaid spool by fixing the position of two or more accelerometers in or onsaid spool at an angle other than 0 degrees, 90 degrees, 180 degrees, or270 degrees such that when a first accelerometer is rotating past 0degrees, the acceleration reading of a second accelerometer will beincreasing or decreasing as an indication of whether said spool isrotating in a payout direction or a take-up direction.

There has thus been outlined, rather broadly, the more importantfeatures of the invention in order that the detailed description thereofthat follows may be better understood and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in this application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of otherembodiments and of being practiced and carried out in various ways.Also, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of description and should not beregarded as limiting. As such, those skilled in the art will appreciatethat the conception upon which this disclosure is based may readily beutilized as a basis for the designing of other structures, methods andsystems for carrying out the several purposes of the present invention.It is important, therefore, that the claims be regarded as includingsuch equivalent constructions insofar as they do not depart from thespirit and scope of the present invention.

Further, the purpose of the foregoing abstract is to enable the U.S.Patent and Trademark Office and the public generally, and especially theengineers and practitioners in the art who are not familiar with patentor legal terms or phraseology, to determine quickly from a cursoryinspection the nature and essence of the technical disclosure of theapplication. The abstract is neither intended to define the invention ofthe application, which is measured by the claims, nor is it intended tobe limiting as to the scope of the invention in any way.

Therefore, it is an object of the present invention to provide a new andimproved reel apparatus, system and method of utilizing same that mayprovide constant tension and constant slippage settings on an umbilicalon a spool on an offshore reel whose deployment is controlled by themovement of a drilling riser by using multiple accelerometers todetermine the direction of rotation of the spool.

Furthermore, an object of the present invention is to provide a new andimproved reel apparatus, system and method of utilizing same to providemultiple accelerometers to determine the direction of rotation of anoffshore reel to determine when during the recovery of an umbilical, theumbilical layer wrap is completed and the radius from the center of thespool to the center of the umbilical becomes greater such that greatertorque will be required to maintain a constant tension setting.

Another object of the present invention is to provide a new and improvedreel apparatus, system, and method of utilizing same that may usemultiple accelerometers to determine the direction of rotation of anoffshore reel to determine when during the recovery of an umbilical, theumbilical layer wrap is completed and the radius from the center of thespool to the center of the umbilical becomes greater such that greatertorque will be required to maintain a constant slippage setting.

Yet another object of the present invention is to provide a new andimproved reel apparatus, system, and method of utilizing same that mayuse multiple accelerometers to determine the direction of rotation of anoffshore reel to determine when during the deployment of an umbilical,the umbilical layer unwrap is completed and the radius from the centerof the spool to the center of the umbilical becomes less such that lesstorque will be required to maintain a constant tension setting.

Still another object of the present invention is to provide a new andimproved reel apparatus, system, and method of utilizing same that mayuse multiple accelerometers to determine the direction of rotation of anoffshore reel to determine when during the deployment of an umbilical,the umbilical layer unwrap is completed and the radius from the centerof the spool to the center of the umbilical becomes less such that lesstorque will be required to maintain a constant slippage setting.

It is a further object of the present invention to provide a new andimproved reel apparatus, system and method of utilizing same, which isof a durable and reliable construction and may be utilized in numeroustypes of reel and or winch applications.

An even further object of the present invention is to provide a new andimproved reel apparatus, system and method of utilizing same, which issusceptible to a low cost of manufacture, installation and labor, whichaccordingly is then susceptible to low prices of sale to the consumingindustry, thereby making such a system economically available to thosein the field.

Still another object of the present invention is to provide a new andimproved reel apparatus, system and method of utilizing same, whichprovides all of the advantages of the prior art while simultaneouslyovercoming some of the disadvantages normally associated therewith.

These, together with other objects of the invention, along with thevarious features of novelty, which characterize the invention, arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages, and the specific objects attained by its uses,reference should be had to the accompanying drawings and descriptivematter in which there are illustrated preferred embodiments of theinvention.

BRIEF DESCRIPTION OF THE PICTORIAL ILLUSTRATIONS, GRAPHS, DRAWINGS, ANDAPPENDICES

The invention will be better understood and objects other than those setforth above will become apparent when consideration is given to thefollowing detailed description thereof. Such description makes referenceto the annexed pictorial illustrations, graphs, drawings and appendices.

FIG. 1 is a general illustration of a preferred embodiment in accordancewith the invention depicting a system of subsea equipment utilizing areel with the characteristics of this invention.

FIG. 2 is a general illustration of a preferred embodiment in accordancewith the invention depicting a perspective view of a reel utilizing thefeatures of this invention.

FIG. 3 is a general illustration of a preferred embodiment in accordancewith the invention depicting a front view of the reel of FIG. 2.

FIG. 4 is a general illustration of a preferred embodiment in accordancewith the invention depicting an end view of the reel of FIG. 2.

FIG. 5 is a general illustration of a preferred embodiment in accordancewith the invention depicting a perspective view of a slip clutch whichis utilized in this invention.

FIG. 6 is a general illustration of a preferred embodiment in accordancewith the invention depicting a side view of the slip clutch of FIG. 5taken generally along section lines “6-6”.

FIG. 7 is a half section of the cylinder portion of the slip clutchtaken generally along section lines “7-7”.

FIG. 8 is a general illustration of a preferred embodiment in accordancewith the invention depicting a schematic of the implementation of thepresent invention utilizing a single computer module.

FIG. 9 is a general illustration of a preferred embodiment in accordancewith the invention depicting a schematic of the implementation of thepresent invention utilizing a stationary computer module on the frameand a rotating computer module in the spool.

FIG. 10 is a general illustration of a preferred embodiment inaccordance with the invention depicting an independent module utilizedto update the modules of the schematics in FIGS. 8 and 9.

FIG. 11 is a general illustration of a preferred embodiment inaccordance with the invention depicting a schematic of theimplementation of the present invention.

DETAILED DESCRIPTION OF INVENTION

Referring to the illustrations, drawings and pictures, referencecharacter 10 generally designates a new and improved reel apparatus,system and method of using same that may generally utilizeaccelerometers for determining the rotational direction of an offshorereel as a component of maintaining a constant tension and constantslippage setting on the umbilical of the offshore reel as the radius tothe umbilical varies and the deployment direction is reversed. Invention10 is generally used with reels and or winches with offshoreapplications but is to be understood that invention 10 may be utilizedfor non-offshore applications and may be utilized in other operationswith reels and or winches in general. For purposes of convenience, thereference numeral 10 may generally be utilized for the indication of theinvention, portion of the invention, preferred embodiments of theinvention and so forth.

Referring now to FIG. 1, a view of a complete system for drilling subseawells 20 is shown in order to illustrate the utility of the presentinvention. The drilling riser 22 is shown with a central pipe 24,outside fluid lines 26, and umbilical, cable or hose 28.

Below the drilling riser 22 is a flex joint 30, lower marine riserpackage 32, lower blowout preventer stack 34 and wellhead or wellheadsystem 36 landed on the seafloor 38.

Below the wellhead 36, it can be seen that a hole was drilled for afirst casing string 40, that first casing string 40 was landed andcemented in place, a hole drilled through the first casing string 40 fora second casing string 42, the second casing string 42 cemented inplace, and a hole is being drilled for a third casing string by drillbit 44 on drill string 46.

The lower blowout preventer stack 34 generally comprises a lowerhydraulic connector for connecting to the subsea wellhead system 36,usually 4 or 5 ram style blowout preventers, an annular preventer, andan upper mandrel for connection by the connector on the lower marineriser package 32, which are not individually shown but are well known inthe art.

Below outside fluid line 26 is a choke and kill (C&K) connector 50 and apipe 52 which is generally illustrative of a choke or kill line. Pipe 52goes down to valves 54 and 56, which provide flow to or from the centralbore of the blowout preventer stack as may be appropriate from time totime. Typically, a kill line will enter the bore of the blowoutpreventers below the lowest ram and has the general function of pumpingheavy fluid to the well to overburden the pressure in the bore or to“kill” the pressure. The general implication of this is that the heaviermud cannot be circulated into the well bore, but rather must be forcedinto the formations. A choke line will typically enter the well boreabove the lowest ram and is generally intended to allow circulation inorder to circulate heavier mud into the well to regain pressure controlof the well. Normal circulation is down the drill string 46, through thedrill bit 44.

In normal drilling circulation, mud pumps 60 take drilling mud 62 frommud tank 64. The drilling mud 62 will be pumped up a standpipe 66 anddown upper end 68 of the drill string 46. It will be pumped down thedrill string 46, out the drill bit 44, and return up the annular area 70between the outside of the drill string 46 and the bore of the holebeing drilled, up the bore of the second casing string 42, through thesubsea wellhead system 36, the lower blowout preventer stack 34, thelower marine riser package 32, up the drilling riser 22, out a bellnipple 72 and back into the mud tank 64.

During situations in which an abnormally high pressure from theformation has entered the well bore, the thin walled central pipe 24 istypically not able to withstand the pressures involved. Rather thanmaking the wall thickness of the relatively large bore drilling riserthick enough to withstand the pressure, the flow is diverted to a chokeline or outside fluid line 26. It is more economical to have arelatively thick wall in a small pipe to withstand the higher pressuresthan to have the proportionately thick wall in the larger riser pipe.

When higher pressures are to be contained, one of the annular or ramblowout preventers are closed around the drill pipe and the flow comingup annular area 70 around the drill pipe is diverted out through chokevalve 54 into the pipe 52. The flow passes up through C&K connector 50,up outside line(s) 26, which is attached to the outer diameter of thecentral pipe 24, through choking means illustrated at 74, and back intothe mud tank 64.

On the opposite side of the drilling riser 22 is shown cable or hose 28coming across a sheave 80 from a reel 82 on vessel 84. The cable or hose28 is shown characteristically entering top 90 of the lower marine riserpackage 32. These cables 28 typically carry hydraulic, electrical,multiplex electrical, or fiber optic signals. Typically, there are atleast two of these cable 28 systems for redundancy, which arecharacteristically painted yellow and blue. As the umbilicals 28 enterthe top 90 of the lower marine riser package 32, they typically enter acontrol pod 92 to deliver their supply or signals. Hydraulic supply isdelivered to one or more dual hydraulic accumulators 94 located on thelower marine riser package 32 or the lower blowout preventer stack 34 tostore hydraulic fluid under pressure until needed.

Referring now to FIG. 2, the reel 82 is shown in greater detail. Reel 82has frame 100, lifting padeyes 102, 104, 106 and 108, spool 110 havingflanges 111 and drum 112 mounted on axle 113 and bearing 114, slipclutches 116, motor 118, swivel 120, levelwind assembly 122 mounted onbanana shaped mounting 124, control box 126, and gear or sprocket 128.Swivel 120 can be hydraulic, electrical, fiber optic, or a combinationof any of these. Gear or sprocket 128 is mounted on slip clutches 116,which are fixed to spool 110.

Also shown on reel 82 are frame control module 130 and spool controlmodule 132 which is shown inside spool 110.

Referring now to FIG. 3, the relationship of slip clutches 116 and theframe control module 130 is shown such that as spool 110 rotates, eachof the slip clutches 116 pass near frame control module 130. As will bediscussed later, each time slip clutch 116 passes the frame controlmodule 130, they will be detected and counted to determine both thenumber of rotations of the spool 110 and the direction of rotation ofthe spool 110. In an alternate embodiment, accelerometers on or withinspool 110 will provide this capability.

Referring now to FIG. 4, slip clutches 116A, 116B and 116C are seen,with the fourth slip clutch 116D being hidden behind control box orpanel 126. This means that for each rotation of the spool 110, spoolcontrol module 132 will see four indications, so will divide the numberby 4 to get the actual number of rotations. Access covers 134 and 136are shown on the end of spool 110. These give access to the inside ofthe spool 110 to install and service spool control module 132.

Referring now to FIG. 5, a perspective view of one of slip clutches 116is seen, showing mounting bolts 150 to fix it to the side of spool 110,brake pads 152 and 154 to engage the gear or sprocket 128 and provide africtional gripping force, and cylinder 156, which provides controlledloading to regulate the frictional slipping load.

Referring now to FIG. 6, a view of slip clutch 116 is shown according tothe view “6-6” taken from FIG. 5. Gap 158 is shown between brake pads152 and 154 for slidable receipt of gear or sprocket 128.

Referring now to FIG. 7, a half section of cylinder 156 is shown takenfrom section “7-7” of FIG. 6. Spring washers 170 provide a force againstpiston 172, which in turn loads brake pad 152 through end 174. Regulatedair pressure through port 176 on piston area 178 provides a force tooffset the force of spring washers 170, regulating the force on end 174,and therefore, brake pad 152 to adjust the force required to cause gearor sprocket 128 to slip. Regulated air pressure through port 180 andporting 182 in piston 172 act on piston area 184 of piston 172 to beadditive to the force of spring washers 170 when greater frictionalforce is desired. Piston cap 186 is rotated on threads 188 to provide aninitial mechanical adjustment to the magnitude of force from springwashers 170.

Referring now to FIG. 8, box 200 generally encompasses the mechanicalcomponents of reel 82, box 202 generally encompasses the components ofthe local control panel 126, box 204 generally encompasses thecomponents of the frame control module 130, and box 206 generallyencompasses the components of the driller's control panel.

Box 200 includes spool 110, axle 113, slip clutches 116A to 116D, airswivel 210, air supply 212, air shutoff valve 214, air motor 216 withgear or sprocket 218 mounted, driven gear or sprocket 220, and levelwinddrive motor 222. Driven gear or sprocket 220 is shown aligned with gearor sprocket 218 and is also shown with a face view having fourprotrusions 224 at 90 degrees. The protrusions 224 are likely a portionof the slip clutches 116 but they can be other quantities and othercomponents. Brakes 226 are shown and will be operated by control box126.

Box 202 includes the components of a pneumatic control box, which wouldprovide constant torque control of a reel, and some components whichchange it to having constant tension operation, as will be described asfollows.

Box 204 is the control box, which includes the components which convertthe reel to constant tension operation. Proximity sensor(s) or sensingcomponent(s) 230 and 232 can be acoustic, laser, microwave, or othermeans to detect when the protrusions 224 pass by. Further, they arepositioned such that both will sense protrusion 224 one after the other,but the second to sense protrusion 224 will also sense before the firststops sensing. Sensing component 230 is the primary sensing componentand sensing component 232 is the secondary sensing component. Whensensing component 230 first senses one of the protrusions 224, sensingcomponent 232 will be checked to see if it is sensing at the same time.If sensing component 232 is sensing when sensing component 230 startssensing protrusion 224, it will mean that the reel is rotating in thetake-up direction. If sensing component 232 is not sensing when sensingcomponent 230 starts sensing protrusion 224, it will mean that the reelis rotating in the payout direction.

Processing computer 240 is initially set up with inputs on the spooldrum diameter, spool width, spool flange diameter, umbilical diameter,the starting dimension from the outer diameter of the spool flange, andthe distance from the side of the spool flange to the current umbilicalposition. The processing computer 240 receives the indications fromsensing components 230 and 232, calculates the current wrap of theumbilical on the spool, and determines the appropriate motor airpressure to provide the appropriate torque and the appropriate slipclutch air pressure for port 176 of FIG. 7 to set the appropriateslippage setting. The general goal of these calculations is to end upwith a constant tension pull on the umbilical, e.g. 1000 lbs., and anappropriate slippage setting on the spool, e.g. 1,500 lbs. umbilicaltension. This umbilical tension setting and slippage setting is toremain relatively constant from a full spool starting the lowering ofthe blowout preventer stack to its landing on the seafloor and back upto the surface. This not only involves the fact that the motor torqueand slippage settings must change each time the umbilical starts on newwrap level, but also that simply reversing the reel has frictionalhysteresis assisting you in one direction and working against you in theother direction.

The computed appropriate motor air pressure is sent to the motor alongline 250 to selector valve 252, to large bore pressure regulator 254,through large bore selector valve 256, and then to air motor 216. Themethod of generating the appropriate air motor pressure signals is tomeasure the pressure in line 250 using pressure transmitter 260 andsending the information back to the processing computer 240 along wire262. If the air pressure in line 250 is low, processing computer 240sends a signal through wire 264 to valve 266 to temporarily open thevalve and let the higher supply pressure in supply line 268 vent intoline 250. If the air pressure in line 250 is low, processing computer240 sends a signal through wire 270 to valve 272 to temporarily open thevalve and vent the pressure in line 250 to reduce the pressure.Processing computer 240 is programmed in a repetitive loop, so it willrepeatedly check the pressure in line 250 through pressure transmitter260, continually making sure the pressure in line 250 is within therequired pressure band.

When deploying the umbilical and all the umbilical is deployed for awrap and the reel starts to deploy from the next lower wrap, the radiusis reduced so the spool/motor torque requirement is reduced. At thattime the computer 240 computes the lower pressure required for line 250and begins pulsing valve 272 until the pressure is in the proper range.Alternately, when recovering the umbilical as the blowout preventerstack returns to the surface and the umbilical begins wrapping on thenext higher layer, the computer 240 begins pulsing valve 266 to increasethe pressure in line 250 to the required computed level.

Similarly, a signal is calculated by processing computer 240 and builtin line 280 for slip clutches 116A, 116B, 116C and 116D using pressuretransmitter 282, valve 284 to increase the pressure, and valve 286 toreduce the pressure. In this case the signal in line 280 is communicatedto the slip clutches 116A, 116B, 116C and 116D through air swivel 210.Air swivel 210 can be made integrally with the axle 113 or can be a slipon air swivel 210 as is illustrated in FIG. 8.

Box 206 shows a single valve 290, which is mounted in a remote locationsuch as the driller's control house. Valve 290 is a two positiondetented valve and in the present position, the pressure in line 292 issimply vented. This means that the air signal in line 250 will becommunicated through valve 252 to regulator 254 and sets the pressure onthe air motor 216 as determined by the processing computer 240.Similarly the air signal in line 280 will be communicated through valve298 to the slip clutches 116A, 116B, 116C and 116D as determined by theprocessing computer 240. When valve 290 is moved to the alternateddetent position, higher pressure air supply from line 294 is introducedinto line 292 shifting valve 252 to allow the pressure from the manualthrottle 296 to control the motor pressure and shifting valve 298 tovent the air pressure from the slip clutches 116A, 116B, 116C and 116D.This returns the reel to what is known as constant torque control, or areel, which simply maintains the present spool torque until the throttleis changed and has no adjustment on the slip clutch settings. Valve 300is the brake control valve.

Infrared port 302 is used to refresh the computer program in processcomputer 240 through line 304 when an upload module as will be describedlater is engaged with profile 306 for proper alignment.

Referring now to FIG. 9, a schematic similar to FIG. 8 is illustrated,with boxes 202 and 204 being identical. Reel box 200 is replaced withreel box 310 and box 204 is replaced with box 312 and box 314.

Box 314 is also shown to be located inside spool 110 as shown in box 310rather than on the frame as box 312 and box 204 are. Whereas box 204provided a single processing computer 240 to control both the motorpressure and the slip clutch pressure, in this configuration box 312controls the motor pressure and box 314 controls the slip clutchpressure. One effect of this is that the signal is going through theswivel in the opposite direction, and another is that you no longer needa swivel if you make the battery pack 315 within box 314 large enough torun several trips to the seafloor or sufficient air supply can besupplied in air tank 316 though connector 317 or air swivel 210 to powerair motor 318 which drives generator 319 to keep battery pack 315charged.

Box 310 shows that the air supply line 268 is taken by air line 320,through valve 322, line 324 and exits from the swivel 210 as air line326, which goes to power the box 314. Whenever the valve 290 in box 206is actuated and applies pressure to line 292, valve 322 is shifted andthe pressure in lines 324 and 326 is dumped returning the slip clutches116A-116D to the default constant torque (non-adjustable) mode.

Box 312 includes all the components of box 204 of FIG. 8 except thecomponents 280, 282, 284 and 286, which were used to control the settingon slip clutches 116A, 116B, 116C and 116D, which are included in box314.

Infrared port 325 is used to refresh the computer program in processcomputer 327 through line 328 when an upload module as will be describedlater is engaged with profile 330 for proper alignment.

Box 314 is located within the spool 110 (as shown in box 310), it doesnot have the reference information which box 204 provided.Accelerometers 350 and 352 are provided to detect rotations androtational direction as will be described later. As was done in FIG. 8,this will be used to determine whether the umbilical is going to thenext outer or the next inner wrap when it reaches either of the sideflanges on the spool.

The computation of the needed slip clutch pressure is done in processcomputer 354 and sent to the slip clutches 116A, 116B, 116C and 116Dalong lines 356 and 358. Valve 359 is provided between lines 356 and 358and is opened by pressure from the supply air line 326 along line 360 toallow the computed signal to pass. If the supply pressure is reduced tozero, the supply signal in line 360 is vented and the reel returns toconstant torque operation.

A signal is calculated by processing computer 354 and built in line 356for slip clutches 116A, 116B, 116C and 116D using pressure transmitter362, valve 364 to increase the pressure, and valve 366 to reduce thepressure, similarly as pressure transmitter 282, valve 284, and valve286 were used in FIG. 8.

Infrared port 370 is used to refresh the computer program in processcomputer 354 through line 372 when an upload module as will be describedlater is engaged with profile 374 for proper alignment.

Referring now to FIG. 10, in one full rotation of spool 110, theaccelerometers will see plus one-g's and minus one-g's and can count theg-cycles as rotations. When primary accelerometer 331 is at one-gdisplaced as shown, secondary accelerometer 332 can be positioned at 45degrees as shown towards the payout direction 361. This angle is anexample, the actual angle can be any angle other than 0 degrees, 90degrees, 180 degrees, or 270 degrees. When the primary accelerometer 331is at zero-g's, whether the secondary accelerometer 332 is reading plusone or minus one-g's will tell the direction of rotation. In this case,if the g-readings are declining it will mean that the spool 110 isrotating in the payout direction. If the g-readings are increasing itwill mean that the spool 110 is rotating in the take-up direction. Thisinformation can be fed back into the process computer 354 to determinewhen the umbilical comes to the end of a wrapping a layer whether to addto the radius to the umbilical or to subtract from it.

Referring now to FIG. 11, an upload module 380, which as a profile 382for convenient engagement and alignment with profiles 306, 330, and 374when process computers 240, 327, or 354 need to be initially programmedor refreshed. Infrared transmitter 384 engages infrared port 302, 325,or 370 for initially programming or refreshing the appropriate processcomputers. Process computer 388 is uploaded from a standard computerthrough a USB or other port 390, which is made explosion proof by anappropriate cap protector 392. Lines 394 connect the port 390 to processcomputer 388 and line 396 in turn connects process computer 388 to theinfrared port 384.

When upload module 380 is taken to refresh a process computer on thereel, it will often be in the hazardous explosion prone area of anoffshore drilling rig. For this reason all modules used need to beexplosion proof. In this case the switches required to operate theupload models are magnetic switches buried in solid potting material397. The other modules described before will likely be of the sameconstruction. Magnet 400 is used to operate the switches with functionssuch as off and on 402, enter, upload in upload mode 404 or download indownload mode 406, increase reading 408, and decrease reading 410.Readout 412 will display the readings of the current mode beingadjusted. Likely only the off and on, upload, and download buttons willbe used and most programming will simply be input through port 390.

Invention 10, therefore, contemplates a method of using at least twoaccelerometers in automatically determining the rotational direction ofthe spool on a reel as a component of automatically maintaining arelatively constant tension and a relatively constant slippage load onan umbilical, which is deployed from a spool on a reel by being clampedto a subsea drilling riser where said relatively constant tension isdetermined by the torque on a motor and said relatively constantslippage load is determined by the frictional load on one or more slipclutches, comprising determining an initial radius to said umbilical onsaid spool, the diameter of said umbilical, the distance between thefirst side flange and the second side flange of said spool, and thedistance of said umbilical from a first side flange of said spool,counting the rotations of said spool, and determining the direction ofrotation of said spool by fixing the position of two or moreaccelerometers in or on said spool at an angle other than 0 degrees, 90degrees, 180 degrees, or 270 degrees such that when the first of saidaccelerometers is rotating past 0 degrees, the acceleration reading ofsaid second of said accelerometers will be increasing or decreasing asan indication of whether said spool is rotating in the payout directionor the take-up direction.

Invention 10 also contemplates a method that may be further comprisingcalculating approximately when said umbilical moves to another layer andchanges the radius to said umbilical, automatically adjusting said motortorque when said radius to said umbilical changes, generally inproportion to the radial change of said umbilical, and automaticallyadjusting said slippage load when said radius to said umbilical changes,generally in proportion to the radial change of said umbilical. Themethod may be further comprising said umbilical is wire, cable, hose orthe like.

Invention 10 still also contemplates a method that may be furthercomprising calculating an appropriate motor pressure to provide saidtorque, having a gas pressure signal to control said motor, andmeasuring the pressure of the signal to said motor (with a pressuretransmitter) within connecting components, when said pressure signal tosaid motor is lower than said appropriate motor pressure pulsing a firstvalve connected to gas supply pressure to increase said pressure signalto said motor and when said pressure signal to said motor is higher thansaid appropriate motor pressure pulsing a second valve to vent some ofthe gas pressure to decrease said pressure signal to said motor. Themethod may be further comprising a control panel having a valve whichwhen actuated blocks the automatic functions of the system and changesit to a manual operator control system.

Invention 10 may further contemplate a method that may be furthercomprising adjusting said motor torque when said direction of rotationof said spool changes as a function of the frictional hysteresis of saidreel. The method may be further comprising adjusting said slippage loadwhen said direction of rotation of said spool changes, generally as afunction of the frictional hysteresis of said reel. The method may befurther comprising said determining of the direction of rotation of saidspool is done automatically. The method may be further comprising saidgas is air.

It is still further contemplated to provide a reel assembly for anoffshore umbilical comprising a frame having an axle; a spool havingflanges and a drum mounted on said axle wherein said spool is adapted tohold said offshore umbilical; a motor adapted to rotate said spool; atleast two accelerometers attached to said spool and adapted to detectrotational direction of said spool; and a processing computer incommunication with said at least two accelerometers and said motor.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. Furthermore, no limitations are intended to thedetails of construction or design herein shown, other than as describedin the claims below. It is therefore evident that the particularembodiments disclosed above may be altered or modified and all suchvariations are considered within the scope and spirit of the invention.Accordingly, the protection sought herein is as set forth in the claimsbelow.

Changes may be made in the combinations, operations, and arrangements ofthe various parts and elements described herein without departing fromthe spirit and scope of the invention. Furthermore, names, titles,headings and general division of the aforementioned are provided forconvenience and therefore, should not be considered limiting.

What is claimed is:
 1. A method of using at least two accelerometers inautomatically determining a direction of rotation of a spool, said spoolhaving a horizontal spool axis, a first spool end and a second spoolend, on a reel as a component of automatically maintaining a relativelyconstant tension and a relatively constant slippage load on an umbilicalwhich is deployed from said spool on said reel by being clamped to asubsea drilling riser where said relatively constant tension isdetermined by a motor torque on a motor and said relatively constantslippage load is determined by a frictional load on one or more slipclutches, comprising: determining an initial radius to said umbilical onsaid spool, a diameter of said umbilical, a distance between a firstside flange and a second side flange of said spool, and a distance ofsaid umbilical from said first side flange of said spool; counting therotations of said spool; and determining said direction of rotation ofsaid spool by fixing the position of said at least two accelerometers inor on said first spool end or second spool end at an angle other than 0degrees, 90 degrees, 180 degrees, or 270 degrees in relation to saidhorizontal spool axis such that when a first accelerometer is rotatingpast 0 degrees, the acceleration reading of a second accelerometer willbe increasing or decreasing as an indication of whether said spool isrotating in a payout direction or a take-up direction.
 2. The method ofclaim 1 further comprising: calculating approximately when saidumbilical moves to another layer and a radial change of said umbilical;automatically adjusting said motor torque when said radius to saidumbilical changes, generally in proportion to said radial change of saidumbilical; and automatically adjusting said slippage load when saidradius to said umbilical changes, generally in proportion to said radialchange of said umbilical.
 3. The method of claim 1 wherein saidumbilical is wire, cable, or hose.
 4. The method of claim 1 furthercomprising: calculating an appropriate motor pressure to provide saidmotor torque, having a gas pressure signal to control said motor; andmeasuring a pressure signal to said motor within connecting components,when said pressure signal to said motor is lower than said appropriatemotor pressure pulsing a first valve connected to a supply of gaspressure to increase said pressure signal to said motor and when saidpressure signal to said motor is higher than said appropriate motorpressure pulsing a second valve to vent some of said gas pressure todecrease said pressure signal to said motor.
 5. The method of claim 1further comprising a control panel having a valve which when actuatedblocks the automatic functions of the system and changes it to a manualoperator control system.
 6. The method of claim 1 further comprisingadjusting said motor torque when said direction of rotation of saidspool changes, generally as a function of a frictional hysteresis ofsaid reel.
 7. The method of claim 1 further comprising adjusting saidslippage load when said direction of rotation of said spool changes,generally as a function of a frictional hysteresis of said reel.
 8. Themethod of claim 1 further comprising determining said direction ofrotation of said spool is done automatically.
 9. The method of claim 4wherein said gas is air.